Hmm, a mixed bag.
But it answers my initial question. . . and leaves me with a bunch more.
Diesel Purge then is not a technique, but a product which claims to clean my injectors?
I just watched Dieselgiant's video of the acceleration he got out of his 300CD with a valve adjustment and Diesel Purge. Pretty impressive. Still, I suppose if I were going to do it right I'd dismantle the injector and labor with the pick and brush.

BTW the forum here is a boon. I would never have bought an MB without it. Thanks to all who contribute.

TOM